The present invention relates to a locking and adjustment device particularly usable for ski boots of the rear-entry type.
Among known devices, suitable for example for fastening the quarters of a ski boot, U.S. Pat. No. 4,433,456 filed by the same Assignee discloses a closure device comprising a box-like body associated with a first boot portion and provided with a knob actuating a spool for winding at least one cable associated with another boot portion to be loosened or tightened relatively to the first boot portion.
The device furthermore comprises ratchet-gear means controlled by said knob, adapted to lock the spool in any position during the rotation of the knob in one direction and to unlock said spool upon the rotation of the knob in the opposite direction.
To reduce the locking effort, a reduction ratio is provided, while the stroke limit for winding the cable is obtained by means of a particular arrangement of the teeth.
Though said device is undoubtedly valid, it has some disadvantages, being structurally rather complicated, therefore constructively onerous, the range of transmission ratio being furthermore reduced since it is limited by dimensional requirements due to the particular structure of said device.
As a partial solution to these disadvantages, European Pat. No. 0 132 744, filed by the same Assignee, discloses a device for actuating a foot instep presser alone composed of an actuation element comprising a spool for winding a cable rigidly associated in rotation with a knob supported, with the possibility of rotation and axial translatory motion, by a fixed body associated with the shell.
Though said device is structurally simpler than the preceding one, it has a direct transmission which makes it suitable practically only for securing the foot presser, great efforts not intervening in this operation.
The device furthermore provides a stroke limit constituted by a tooth protruding from the knob, which interacts with an abutment on the fixed part of the support: this configuration however allows only one rotation of 360 degrees.
The same Assignee filed a U.S. Pat. No. 4,620,379 disclosing a closure device which allows the simultaneous locking of the quarters and of the foot.
This device, however, also has a disadvantage, the locking being the same both for the quarters and for the foot, this not being optimum since the two require separate adjustments.
A French patent application, No. 2570257 filed on Sept. 14, 1984, is also known, wherein a circular device is illustrated which effects a locking on the foot instep and of the quarters, said device winding a single cable acting thereon.
Among the disadvantages observable in said known type of device, it is noted that the locking occurs without differentiations between the foot instep and the quarters, furthermore, there is an insufficient rear support since, during the extension of the leg, the cable exerts a greater pressure on the foot instep and, vice versa, it tends to slacken the pressure when the skier flexes his or her leg, thus being ineffective in the conditions of actual stress.
The device furthermore provides the unlocking of the cable by means of a ratchet lever actuatable by the skier: however, when said lever is subject to high loads, that is to say for very tight lockings, the skier has to exert quite an effort and, furthermore, only the rapid unwinding of the cable is possible.